1. Field of the Invention
This invention relates to a sound reproducing device for playing a record disc having a plurality of recorded grooves. More particularly, the present invention relates to such a sound reproducing device comprising an index tracking portion which is a notch formed by cutting away a part of a flange continuously formed around the periphery of a rotary record disc unit, and a center pin rotatably supporting the record disc unit which center pin carries a push button type rotary knob thereon exposed outside a casing in such a manner that the center pin is normally urged together with the push button type rotary knob, toward the outside of the casing by a spring biasing an indexing arm.
2. Description of the Prior Art
A simplified sound reproducing device, capable of selectively reproducing a specific recorded item on a record disc having a plurality of recorded grooves each carrying respective recorded items, has been developed and becomes well known, e.g., such as described in Japanese Patent Examined Publication No. Sho 51(1976)-19763, corresponding to U.S. Pat. No. 3,712,629 and to British patent specification No. 1,336,749.
This prior art simplified sound reproducing device functions in such a manner that:
if an operator depresses a selection pole for indexing a specific item on a record disc, it acts to push an inclined face of a stylus force releasing wheel to move a stylus force releasing pole to make the stylus force releasing wheel rotate, and then a stylus force releasing pole carried by the stylus force releasing arm travels together with the stylus force releasing wheel and raises a speaker unit, allowing a pickup to return to the starting point of sound reproduction of a specific record disc unit.
At the same time, the selection pole locks a stopper pin disposed in the record disc unit and tentatively stops the rotation of the record disc unit, thereby locating the specific recorded groove at a position where the pickup, which has already returned to the aforesaid starting point of reproduction, can engage the recorded groove, while by the operator's releasing of the depression of the selection pole, the stylus force releasing pole will retract together with the stylus force releasing wheel and release the supply of current to the speaker unit, thereby importing a stylus force to the pickup.
Accordingly, in this prior art device, a stylus force can be undesirably imparted to the pickup halfway through its returning travel to the starting point of sound reproduction, and thereby the desired record groove cannot be selected, unless the operator keeps his depression of the selection pole until its stopper pin engages the specific selection pole which has been depressed. The period of time required for effecting engagement between the stopper pin and the selection pole varies depending upon the relative position between the stopper pin and the selection pole, and therefore, the operator himself cannot forecast the necessary period of time. Consequently, the sound reproducing device mentioned above has drawbacks with respect to its lack of both reliability in selection and fast operability.
A device disclosed in Japanese Laid-Open (unexamined) Patent Publication No. Sho 60(1985)-50701, corresponding to U.S. Pat. No. 4,482,990, has been provided, with the intention of obviating the aforesaid drawbacks. However, this device was found to be disadvantageous in simplifying the device, because of the fact that the stylus force releasing means and the indexing means were complicated.
Another sound reproducing device having improved steadiness of selection and rapidity of operation has been disclosed by Japanese Laid-Open (unexamined) Patent Publication No. Sho 60(1985)-76001, corresponding to U.S. Pat. No. 4,541,085, with an intention to obviate the aforesaid drawbacks.
However, this device was also found to be disadvantageous in simplifying, because the stylus force releasing means and the indexing means were also complicated.
Moreover, a simplified sound reproducing device capable of selectively playing a record disc having a plurality of recorded grooves and further provided with a rotary dial for selecting the item to be reproduced by directing it to the item to be selected has already been developed and has been disclosed by Japanese Laid-Open (unexamined) Patent Publication No. Sho 58(1983)-17501, corresponding to U.S. Pat. No. 4,433,404 and to British Pat. No. 2,103,006-B.
However, this device has also proved to be unsatisfactory, particularly as a toy for training infants, that is, even if the user turns the rotary dial to the indexing mark or symbol to be played, the rotary dial will start rotation following the rotation of the record disc unit, thereby the indicated item which has just been selected for playing would be unplayed.
In addition, a further device having a center pin for rotatably receiving a record disc unit in which the center pin may be depressed for the purpose of releasing the stylus force has also been proposed and publicly known in Japanese Laid-Open (unexamined) Patent Publication No. Sho 57(1982)-152568, corresponding to U.S. Pat. No. 4,404,668.
However, this device has also drawbacks that it uses a plurality of selecting poles and many parts and thereby becomes very complicated in construction.